EP0574208B1 - Membre de charge et appareil de formation d'images avec un membre de charge par contact - Google Patents

Membre de charge et appareil de formation d'images avec un membre de charge par contact Download PDF

Info

Publication number
EP0574208B1
EP0574208B1 EP93304390A EP93304390A EP0574208B1 EP 0574208 B1 EP0574208 B1 EP 0574208B1 EP 93304390 A EP93304390 A EP 93304390A EP 93304390 A EP93304390 A EP 93304390A EP 0574208 B1 EP0574208 B1 EP 0574208B1
Authority
EP
European Patent Office
Prior art keywords
image bearing
charging
bearing member
gap
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP93304390A
Other languages
German (de)
English (en)
Other versions
EP0574208A2 (fr
EP0574208A3 (fr
Inventor
Takeo c/o Canon Kabushiki Kaisha Yamamoto
Tetsuya C/O Canon Kabushiki Kaisha Kuribayashi
Takao c/o Canon Kabushiki Kaisha Honda
Fumihiro c/o Canon Kabushiki Kaisha Arahira
Hiroyuki c/o Canon Kabushiki Kaisha Osada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP0574208A2 publication Critical patent/EP0574208A2/fr
Publication of EP0574208A3 publication Critical patent/EP0574208A3/fr
Application granted granted Critical
Publication of EP0574208B1 publication Critical patent/EP0574208B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
    • G03G15/0208—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices by contact, friction or induction, e.g. liquid charging apparatus
    • G03G15/0216—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices by contact, friction or induction, e.g. liquid charging apparatus by bringing a charging member into contact with the member to be charged, e.g. roller, brush chargers

Definitions

  • the present invention relates to a charging device and in particular to a charging device for an electrophotographic apparatus in which the charging device causes a charging member to contact the surface of an image bearing member to as to charge the surface.
  • non-contact corona charging devices have been widely used in electrophotographic machines such as laser beam printers and electrostatic recording machines, for electrically charging the image bearing members of such machines.
  • Corona charging devices use an air discharge and are effective for electrically charging the surface to be charged uniformly to a predetermined potential. However, they require a high voltage source and produce a significant amount of ozone.
  • a contact charging device is usable with a low voltage, and it has the advantage that the amount of the ozone production is small.
  • contact chargers can be considered as a replacement for corona charging devices.
  • Japanese Laid-Open Patent Application No. 51492/1987 and Japanese Laid-Open Patent Application 230334/1987 propose that by forming an oscillating electric field having a peak-to-peak voltage which is twice or more as high as the charge starting voltage when a DC voltage is supplied to the charging member (alternating electric field) between the charging member and the member to be charged such as the photosensitive member, and by using a charging member which is provided with a high resistance layer as the surface layer, the charge uniformity of the photosensitive member is assured.
  • the leakage prevention of current attributable to the pin hole or the defects of the surface of the member to be charged is accomplished.
  • an electrically conductive member such as an electrically conductive fiber brush or an electrically conductive elastic roller
  • a DC voltage is externally applied, by which the electric charge is injected directly into the surface of the member to be charged in the form of a photosensitive member, and the photosensitive member surface is charged to the predetermined potential.
  • FIG. 6 is a schematic view of an example of the contact type device, and the charging device shown in this Figure, is provided with a charging roller 2 and a voltage source 3.
  • the charging roller 2 functioning as the charging member comprises a central core metal 2c, a conductive layer 2b outside it and a resistance layer 2c further outside it.
  • the charging roller 2 is disposed in parallel with the drum-like photosensitive drum 1 functioning as the member to be charged. Simultaneously therewith, the right and left opposite end portions (opposite end portions of the longitudinal direction of the shaft) of the core metal 2c is supported for rotation about an unshown bearings.
  • the charging roller 2 is press-contacted by an urging means (not shown) at predetermined urging force against the surface to be charged 1a of the photosensitive drum 1 surface. It is possible to forcedly drive by a motor with the provision of gear or the like rotating in a direction R2 following the rotation of the photosensitive drum 1 in the direction R1.
  • the voltage source 3 is a bias voltage application voltage source for the charging roller 2. This voltage source 3 and the core metal 2c of the charging roller 2 are connected electrically with each other through a power supply sliding contact 3a. A predetermined bias voltage is applied by a voltage source 3 to the charging roller 2.
  • the charging roller 2 When the photosensitive drum 1 is rotated in a direction indicated by an arrow, the charging roller 2 is driven in the direction of the arrow. At this time, the predetermined bias voltage is applied from the voltage source 3 to the charging roller 2. By doing so, outer peripheral surface of the photosensitive drum 1, that is, the surface to be charged 1a is electrically charged to the predetermined polarity and to the predetermined potential.
  • the charged photosensitive drum 1 is exposed to image light 5 in accordance with the image to be formed by this, an electrostatic latent image is formed.
  • the electrostatic latent image is visualized with the toner in the developing device 6.
  • the visualized toner image is transferred by a transfer charger 7 to a transfer material P.
  • the toner image on the transfer material P having the toner image transferred thereto is fixed by a fixing device (not shown). Thereafter, it is discharged to an outside of the apparatus.
  • the photosensitive drum after the image transfer is cleaned by a cleaning blade 9a of a cleaning device 9 so that the remaining developer (residual toner) is removed. Subsequently, it is discharged by a pre-exposure light device 10 in preparation for the following image formation.
  • a nip N is formed at the contact portion between the surface 1a to be charged of the photosensitive drum 1 and the charging roller 2.
  • a first gap G1 and a second gap G2 are formed, respectively.
  • the gaps G1 and G2 that is, the distance between the surface to be charged 1a and the charging roller 2
  • the first gap gradually decreases toward the nip N
  • the second gap increases gradually away from the nip N.
  • a white stripe having a length of 2 - 10 mm and a width of 0.5 mm or less can be produced in a direction perpendicular to the movement direction of the surface to be charge 1a, so that the stabilized image formation is disturbed.
  • United States Patent Specification No. US-A-4,750,019 discloses electrophotographic image forming apparatus in which a discharging device is located upstream in the direction of movement of a photosensitive image bearing member with regard to a corotron charging device.
  • an image forming apparatus as set out in claim 1.
  • Figure 1 is a schematic view illustrating the structure of an image forming apparatus according to the present invention.
  • Figure 2 is a sectional view illustrating a discharging device according to another embodiment of the present invention.
  • Figure 3 is a sectional view of a discharging device according to another embodiment of the present invention.
  • Figure 4 is a sectional view illustrating a charging roller according to a further embodiment of the present invention.
  • Figure 5 shows an operation sequence of an image forming apparatus.
  • Figure 6 is a sectional view of a conventional image forming apparatus.
  • Figure 1 is a sectional view of an image forming station of an image forming apparatus according to an embodiment of the present invention.
  • a cylindrical photosensitive drum 1 (member to be charged) is rotatably supported in the main assembly (not shown) of the apparatus.
  • the photosensitive drum 1 is a drum type electrophotographic photosensitive member having an electrically conductive base layer 1b made of aluminum or the like, a laminated polymeric material formed thereon, that is, a photoconductive layer (surface to be charged) 1a.
  • the OPC photoconductor in this embodiment is negatively chargeable.
  • the entirety of the photosensitive drum 1 is rotated about a shaft 1d in a direction of an arrow R1 at a predetermined peripheral speed.
  • the charging member 2 is disposed above the photosensitive drum 1.
  • the charging member 2 is contacted to the surface to be charged 1a of the photosensitive drum 1 to uniformly charging (primary charging) to a predetermined polarity and to the predetermined potential.
  • it is of a roller type (charging roller).
  • the charging roller 2 is provided with a core metal 2c, a conductive layer 2b thereon and a resistance layer 2a2 thereon.
  • the longitudinal opposite end portions of the core metal 2c (in the direction perpendicular to the sheet of the drawing of Figure 1) of the charging roller 2 are rotatably supported by unshown bearing members, and it is in parallel with the photosensitive drum 1. It is urged to the surface to be charged 1a of the photosensitive drum 1 by urging means (unshown) at a predetermined urging force. With the rotation of the photosensitive drum 1 in a direction R1, it is driven in a direction R2.
  • a power supply contact 3a contacts the core metal 2c of the charging roller 2.
  • a bias voltage is applied from a voltage source 3 through this contact 3a.
  • the charging roller 2 may be driven by the photosensitive drum 1. It may be positively rotated in the same direction as or in the opposite direction from the surface to be charged 1a of the photosensitive drum.
  • the photosensitive drum which has been subjected to the charging process for uniform charging by the charging roller 2 is exposed to image information through exposure means 5 (laser beam scanning exposure, original image slit exposure or the like, and the latter is used in this embodiment). Then, an electrostatic latent image is formed on the surface 1a to be charged in accordance with the intended image formation.
  • the electrostatic latent image is sequentially developed with the positively charged toner by a developing device 6 into a visualized image.
  • the first toner image is transferred onto the transfer material P by a transfer device 7.
  • the transfer device 7 is provided with a rotatable transfer roller 7a and a voltage source 7b. It is effective to charge the rear of the transfer material P to a polarity opposite from the toner by the roller 7a.
  • the toner image on the photosensitive drum 1 is sequentially transferred onto the upper surface of the transfer material P.
  • the transfer material P is conveyed from an unshown feeding device to the transfer station between the photosensitive drum 1 and the transfer device 7 at the proper timing in synchronism with the rotation of the photosensitive drum 1.
  • the transfer material having received the toner image P transferred thereto is separated from the photosensitive drum 1, and it is conveyed to an unshown fixing device, and the toner image is fixed. Thereafter, it is discharged to an outside of the main assembly of the apparatus, or it is refed to the transfer station if, for example, it should receive an image on its other backside.
  • the photosensitive drum 1 after the image transfer is cleaned by a cleaning blade 9a of the cleaning device 9, so that deposited contamination such as residual toner or the like is removed. Then, the residual charge is removed by the pre-exposure device 10.
  • a discharging device 11 of the present invention is disposed between the cleaning device 9 and the downstream charging roller 2, a discharging device 11 of the present invention is disposed.
  • the pre-exposure device 10 removes the residual charge from the surface to be charged 1a of the photosensitive drum 1 substantially to 0 V.
  • the discharging device 11 is effective to provide the proper charging of the surface to be charged 1a by the charging roller 2. Before describing the charging device 11, the description will be made as to the charging roller 2.
  • the charging roller 2 of this embodiment comprises a core metal 2c, an electrically conductive rubber layer 2b comprising EPDM rubber (terpolymer of ethylene propylene diene) or the like and having a volume resistivity of 10 4 - 10 5 , and an intermediate resistance layer 2a2 of hydrin rubber or the like having a volume resistivity of 10 7 - 10 9 ohm.cm, and a blocking layer 2a1 of Toresin (available from Teikoku Kagaku Kabushiki Kaisha, trade mark) or another nylon material having a volume resistivity 10 7 - 10 10 ohm.cm and having a hardness of 50 - 70 degrees (Asker C).
  • the charging roller 2 is contacted to the photosensitive drum 1 with a total pressure of 1600 g so as to be rotated thereby.
  • first and second small gaps G1 and G2 are formed at the respective upstream and downstream sides of the nip between the roller 2 and surface 1a.
  • the upstream gap G1 gradually decreases toward the nip N in the downstream direction, and the downstream gap G2 increases away from the nip N.
  • the nip extends through substantially the entire length of the charging roller (axial direction). Therefore, the first and second gaps G1 and G2 extend throughout the length of the charging roller 2.
  • the discharging device 11 comprises a light projection device comprising a fuse lamp.
  • the illumination per unit time of the fuse lamp 11 is 5.0 Lux. It irradiates light to a portion forming the first gap G1 along the entire length in synchronism with application of the bias voltage from the voltage source 3 or for a longer period than the bias voltage application period.
  • the surface 1a to be charged is electrically discharged in the portion of the first gap. If the discharging operation is not carried out, that is, when the image forming operation is carried out in the conventional manner shown in Figure 6, a horizontal white stripe is produced from the first sheet to approx. 2000 sheet image forming operations upon forming half-tone and solid black image formations, because the charge movement between the charging roller 2 and the member to be charged 1a occurs in the first gap G1, nip N and the second gap G2.
  • the fuse lamp 11 illuminates the surface to be charged 1a in the first gap G1, by which the electric charge of this portion by the charging roller 2 is removed, and the charging is effected in the nip and the second gap G2.
  • the separation discharge which occurs by the surface to be charged 1a moving through the nip N and the second gap G2, and the white stripe having resulted at the time of halftone or solid black image formation can be avoided.
  • the time period in which the exposure by the lamp 11 is carried out may be the period in which the voltage is applied to the charging roller at the minimum.
  • the region of the drum 1 exposed to the lamp 11 light may be at least the region in which the toner image formation is possible for the next image formation.
  • the region capable of toner image formation is a region in which a toner image can be formed on the drum 1 for any image information.
  • the lamp 11 Since the surface of the photosensitive drum has been electrically discharged by the lamp 10 when the surface is going to reach the nip N, the lamp 11 functions to prevent the surface from being electrically charged by the charging roller 2.
  • the charging device 11 may also function as a pre-exposure device 10.
  • a half mirror 12 is attached to a cleaning blade of the cleaning device 9, and the illumination light from the discharging device 11 (pre-exposure device 10) is divided into the light for discharging the surface to be charged 1a immediately after the cleaning station and the light for discharging the surface to be charged 1a at the first gap G1 for the charging.
  • the illumination light from the discharging device 11 pre-exposure device 10
  • the entire structure is simplified, and in addition, the operational sequence can be simplified.
  • a total reflection mirror or a member finished to a mirror surface by evaporation or metal plating is usable. It is disposed for retraction so that the optical path of the illuminating light is switched between for the cleaning blade 9a and for the first gap G1.
  • a tangent line of the nip N is substantially in accord with the beam from the lamp, as shown in Figures 1 and 2, since then, the light reaches deep into the gap G1.
  • an outer circumference of the photosensitive drum 1, that is, the photoconductive layer la and the conductive base layer 1b, are formed with known transparent photosensitive material, and the discharging is effected with a discharging device 11 disposed inside the transparent photosensitive member with the light amount of 10 Lux.sec by the discharging device 11.
  • the discharging device 11 thus electrically discharge the photosensitive member in the gap G1 along the entire length thereof over the width of 3 mm.
  • the discharging device 11 may include an LED lamp.
  • there is a liability that the light source or the mirror surface may be contaminated with the result that the amount of the light may be reduce by the scattered toner during use thereof or the like.
  • the light source is disposed inside the photosensitive drum, the discharge can be carried out, so that the horizontal white stripe can be avoided without the contamination and with a constant light quantity at all times, and with stability.
  • the charging roller comprises a core metal and three layers thereon. In this embodiment, has two layers on the core metal, as shown in Figure 4.
  • the charging roller 2 shown in Figure 4 comprises a core metal 2c, an electrically conductive layer 2b thereon and a high resistance layer 2a mainly comprising resin material thereon.
  • the discharging device 11 having been described in Embodiments 1 - 4, both can be equally used when the bias voltage to be applied to the charging roller 2 by the voltage source 3 comprises only DC component, and when it is a DC biased AC.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Discharging, Photosensitive Material Shape In Electrophotography (AREA)

Claims (23)

  1. Appareil de formation d'images, comportant :
    un élément mobile (1) porteur d'image qui comprend une couche photosensible (1a) ; et caractérisé par
    un élément de charge (2) conçu pour, en fonctionnement, être en contact avec ledit élément porteur d'image et le charger électriquement, les surfaces de l'élément de charge et de l'élément porteur d'image étant telles qu'un espace (G1) de largeur variable soit formé en amont par rapport au sens du mouvement de l'élément porteur d'image, à partir de la ligne de contact entre les deux éléments, la largeur de l'espace diminuant jusqu'à atteindre la ligne de contact, l'appareil comprenant en outre un moyen (11) de décharge conçu pour projeter de la lumière dans ledit espace.
  2. Appareil selon la revendication 1 et comprenant un moyen destiné à commander le moyen de décharge afin que le moyen de décharge projette de la lumière dans ledit espace lorsqu'une tension de charge est appliquée audit élément de charge.
  3. Appareil selon la revendication 1 ou la revendication 2, dans lequel ledit élément porteur d'image est un tambour rotatif.
  4. Appareil selon l'une quelconque des revendications précédentes, dans lequel l'élément de charge est un rouleau.
  5. Appareil selon la revendication 4, comprenant un moyen destiné à solliciter le rouleau en contact avec l'élément porteur d'image, dans lequel, lorsque l'élément de charge est libre de toute charge mécanique, son diamètre augmente dans des zones sur lesquelles ledit moyen de sollicitation n'agit pas.
  6. Appareil selon la revendication 5, dans lequel ledit moyen de sollicitation agit à proximité immédiate du rouleau et le diamètre du rouleau, lorsqu'il n'est soumis à aucune charge mécanique, augmente vers son centre longitudinal.
  7. Appareil selon la revendication 3 et l'une quelconque des revendications 4 à 6 lorsqu'elle dépend de la revendication 3, dans lequel le dispositif de décharge est conçu pour diriger de la lumière dans l'espace, sensiblement tangentiellement à la surface de l'élément porteur d'image.
  8. Appareil selon l'une quelconque des revendications précédentes et comprenant un moyen d'exposition additionnelle (10) pour décharger l'élément porteur d'image après une opération de formation d'image.
  9. Appareil selon la revendication 8, dans lequel le moyen d'exposition et le moyen de décharge (10) comprennent une source unique de lumière, et un moyen (12) destiné à diviser la lumière provenant de la source de lumière afin qu'une partie de la lumière soit projetée dans ledit espace.
  10. Appareil selon la revendication 9, dans lequel le moyen de division comprend un miroir semi-réfléchissant.
  11. Appareil selon l'une quelconque des revendications précédentes, et comprenant un élément de nettoyage (9) destiné à nettoyer la surface de l'élément porteur d'image.
  12. Appareil selon la revendication 11 lorsqu'elle dépend de la revendication 9 ou de la revendication 10, dans lequel le moyen de division est monté sur ledit élément de nettoyage.
  13. Appareil selon la revendication 8, dans lequel le moyen de décharge (10) est monté de façon à diriger de la lumière vers l'espace à partir d'au-dessous de la surface de l'élément porteur d'image.
  14. Appareil selon la revendication 8 ou la revendication 13, comprenant un moyen destiné à faire fonctionner simultanément le moyen (10) d'exposition additionnelle et le moyen (10) de décharge.
  15. Appareil selon l'une quelconque des revendications précédentes, comportant en outre un moyen de développement destiné à développer à l'aide d'un toner une image latente sur ledit élément porteur d'image, en utilisant la charge dudit élément de charge.
  16. Appareil selon l'une quelconque des revendications précédentes, dans lequel ledit élément de charge (2) comporte une couche électriquement conductrice et une couche à résistance sur cette dernière.
  17. Appareil selon l'une quelconque des revendications précédentes, dans lequel ledit élément de charge (2) comporte une couche électriquement conductrice (2b), une couche à résistance (2a2) sur cette dernière, et une couche qui n'est pas en caoutchouc.
  18. Appareil selon l'une quelconque des revendications précédentes, comportant en outre un moyen de report (7) destiné à reporter une image dudit élément porteur d'image sur un milieu de report.
  19. Appareil selon l'une quelconque des revendications précédentes, comportant en outre un moyen (5) destiné à exposer ledit élément porteur d'image, chargé par ledit élément de charge (2), à la lumière d'une image, dans lequel le potentiel dudit élément porteur d'image, en fonctionnement, est sensiblement constant après qu'il a été chargé par ledit élément de charge (2) et avant qu'il soit exposé par ledit moyen (5) d'exposition à une image.
  20. Appareil selon l'une quelconque des revendications précédentes, comprenant un moyen destiné à appliquer soit une tension continue sans composante alternative entre ledit élément de charge et ledit élément porteur d'image, soit une tension alternative avec une composante continue.
  21. Procédé de formation électrophotographique d'une image, comprenant la charge d'un élément porteur d'image, mobile et photosensible, à l'aide d'un dispositif de charge qui est en contact avec l'élément porteur d'image, et dans lequel les surfaces de l'élément de charge et de l'élément porteur d'image sont telles qu'un espace (G1) de largeur variable est formé en amont par rapport au sens du mouvement de l'élément porteur d'image à partir de la ligne de contact entre les deux éléments, la largeur de l'espace diminuant jusqu'à atteindre la ligne de contact, et comprenant la projection de lumière dans l'espace.
  22. Procédé selon la revendication 21, dans lequel l'élément de charge est un rouleau et l'élément porteur d'image est un tambour, et la lumière est dirigée tangentiellement dans l'espace qui est formé sur le côté d'amont de la zone de serrage entre les deux éléments dans le sens du mouvement de la surface de l'élément porteur d'image.
  23. Procédé selon la revendication 21 ou 22, dans lequel la lumière est projetée dans l'espace en même temps que de la lumière est projetée sur l'élément porteur d'image afin de décharger la surface de ce dernier après la formation et le développement par un toner d'une image.
EP93304390A 1992-06-08 1993-06-07 Membre de charge et appareil de formation d'images avec un membre de charge par contact Expired - Lifetime EP0574208B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP173902/92 1992-06-08
JP17390292A JP3283906B2 (ja) 1992-06-08 1992-06-08 帯電装置

Publications (3)

Publication Number Publication Date
EP0574208A2 EP0574208A2 (fr) 1993-12-15
EP0574208A3 EP0574208A3 (fr) 1994-02-02
EP0574208B1 true EP0574208B1 (fr) 1997-11-12

Family

ID=15969206

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93304390A Expired - Lifetime EP0574208B1 (fr) 1992-06-08 1993-06-07 Membre de charge et appareil de formation d'images avec un membre de charge par contact

Country Status (4)

Country Link
US (1) US5671468A (fr)
EP (1) EP0574208B1 (fr)
JP (1) JP3283906B2 (fr)
DE (1) DE69315123T2 (fr)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69418268T2 (de) * 1993-09-07 1999-09-23 Matsushita Electric Ind Co Ltd Aufladevorrichtung und Bilderzeugungsgerät mit der Aufladevorrichtung
DE69425954T2 (de) * 1993-12-28 2001-01-18 Matsushita Electric Ind Co Ltd Aufladevorrichtung, Bilderzeugungsgerät mit der Aufladevorrichtung und Verfahren zur Herstellung der Vorrichtung
US5983045A (en) * 1996-11-14 1999-11-09 Canon Kabushiki Kaisha Image forming apparatus for forming plural toner images on photosensitive member and for transferring toner images onto transfer material collectively
JPH10148993A (ja) * 1996-11-19 1998-06-02 Canon Inc ２色画像形成装置
KR100228804B1 (ko) * 1997-08-16 1999-11-01 윤종용 전자사진 현상방식을 채용한 화상형성장치에서 접촉대전방식의대전장치
US6337962B1 (en) 1999-08-12 2002-01-08 Canon Kabushiki Kaisha Process cartridge and electrophotographic apparatus
JP2002055521A (ja) * 2000-08-10 2002-02-20 Minolta Co Ltd 現像装置及び画像形成装置
JP5157097B2 (ja) * 2006-07-18 2013-03-06 株式会社リコー 画像形成装置の帯電工程評価方法
CN102356358B (zh) * 2009-09-10 2014-10-01 佳能株式会社 图像形成装置
JP5253487B2 (ja) 2010-12-17 2013-07-31 キヤノン株式会社 画像形成装置
KR101812074B1 (ko) * 2011-03-17 2018-01-30 에스프린팅솔루션 주식회사 현상유닛 및 그를 구비한 화상형성장치
JP5777648B2 (ja) * 2013-01-28 2015-09-09 京セラドキュメントソリューションズ株式会社 シート搬送装置、画像形成装置
JP6827724B2 (ja) 2016-06-30 2021-02-10 キヤノン株式会社 画像形成装置
JP7293894B2 (ja) * 2019-06-14 2023-06-20 京セラドキュメントソリューションズ株式会社 画像形成装置及び画像形成方法

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5664359A (en) * 1979-10-31 1981-06-01 Toshiba Corp Charging device in electrophotographic copying machine
JPS56151976A (en) * 1980-04-26 1981-11-25 Ricoh Co Ltd Cleaning device for two color electrophotographic copying machine
JPS6251492A (ja) * 1985-08-30 1987-03-06 Mita Ind Co Ltd オ−バ−ヘツドプロジエクタ−用シ−ト
US4769676A (en) * 1986-03-04 1988-09-06 Kabushiki Kaisha Toshiba Image forming apparatus including means for removing residual toner
JPS62230334A (ja) * 1986-03-28 1987-10-09 Toshiba Corp 三相交流回転電機
JPH0722675Y2 (ja) * 1986-07-17 1995-05-24 三洋電機株式会社 電子写真装置
JPS642249U (fr) * 1987-06-22 1989-01-09
EP0308185B1 (fr) * 1987-09-14 1993-11-24 Canon Kabushiki Kaisha Dispositif de charge
JPS63170673A (ja) * 1987-12-16 1988-07-14 Toshiba Corp 帯電装置
JPH027663U (fr) * 1988-06-30 1990-01-18
US5119139A (en) * 1989-01-06 1992-06-02 Tokyo Electric Co., Ltd. Electrophotographic image forming apparatus having multiple printing stations
US5307122A (en) * 1989-07-28 1994-04-26 Canon Kabushiki Kaisha Image forming apparatus apparatus unit facsimile apparatus and developer comprising hydrophobic silica fine powder for developing electrostatic images
US5150165A (en) * 1990-04-10 1992-09-22 Canon Kabushiki Kaisha Image forming apparatus having image transfer member
US5198842A (en) * 1990-10-24 1993-03-30 Seiko Epson Corporation Ionographic image forming apparatus
JP2561400B2 (ja) * 1991-07-31 1996-12-04 キヤノン株式会社 電子写真装置及びこの装置に着脱可能なプロセスカートリッジ
JP3134007B2 (ja) * 1991-11-13 2001-02-13 株式会社リコー 画像形成装置

Also Published As

Publication number Publication date
JPH05341626A (ja) 1993-12-24
EP0574208A2 (fr) 1993-12-15
DE69315123T2 (de) 1998-04-02
DE69315123D1 (de) 1997-12-18
US5671468A (en) 1997-09-23
EP0574208A3 (fr) 1994-02-02
JP3283906B2 (ja) 2002-05-20

Similar Documents

Publication Publication Date Title
US5006902A (en) Image forming apparatus having a predetermined voltage applied to the transfer member
EP0563478B1 (fr) Appareil de formation d'images muni d'une électrode de transfert d'images en contact avec le matériau de transfert
EP0574208B1 (fr) Membre de charge et appareil de formation d'images avec un membre de charge par contact
KR19990045532A (ko) 화상형성장치용 대전장치
JP4684617B2 (ja) 画像形成装置
US5587780A (en) Image forming apparatus with different potentials in different developing zones
US20060222400A1 (en) Image forming apparatus
JPH0715608B2 (ja) 残留トナー除去方法及び装置
US5708929A (en) Contact charging image forming apparatus having improved image transfer
JPH04138484A (ja) 画像形成装置
US5649268A (en) Charging device having a voltage with a superimposing component mode having a DC component and an oscillation component and a DC component mode
JPH07114312A (ja) 帯電装置及び画像形成装置
US5321472A (en) Charging member with a bridging electrode structure and charging device using same in an image forming apparatus
JP2000250370A (ja) 電子写真装置
JPH0348870A (ja) 画像形成装置
JPH0758419B2 (ja) プロセスカートリッジ及び画像形成装置
US5172174A (en) Transfer device with insulated shield
JPH07199758A (ja) 画像形成装置
JP2002132022A (ja) 画像形成装置
JP3058736B2 (ja) 画像形成装置
JP2004212542A (ja) 中間転写体・カラー画像形成方法・画像形成装置
JP2626089B2 (ja) 接触帯電装置
JPH08202125A (ja) 画像形成装置の電荷供給装置
JP2003173071A (ja) 帯電装置、プロセスカートリッジ及び画像形成装置
JPH08166755A (ja) 画像形成装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB IT

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19940617

17Q First examination report despatched

Effective date: 19960207

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT

REF Corresponds to:

Ref document number: 69315123

Country of ref document: DE

Date of ref document: 19971218

ITF It: translation for a ep patent filed

Owner name: SOCIETA' ITALIANA BREVETTI S.P.A.

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20110621

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20110608

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20110713

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20110630

Year of fee payment: 19

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20120607

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120607

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20130228

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120607

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130101

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120702

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 69315123

Country of ref document: DE

Effective date: 20130101